Mongol invasions of Anatolia

The Mongol invasions of Anatolia occurred from 1241 to 1255 when the Mongol Ilkhanate general Baiju invaded Anatolia to punish the Seljuk Sultanate of Rum for breaching its tributary status.

Background
Following the assassination of the Khwarezmian prince Jalal ad-Din Mingburnu in 1231, the Khwarezmian empire ceased to exist, and the Seljuk Turks, Cilicia, and Georgia became vassals of the Mongol Empire. Peace reigned for ten years as the Mongols focused on their invasion of Europe, but Ogedei Khan's death in 1241 weakened the empire. In 1241, the Mongol governor Baiju asked the Seljuk sultan Kaykhusraw II to renew his vassal oath. Kaykhusraw refused and instead raided another Mongol vassal, Georgia, leading to war.

War
The Mongols pushed the Seljuks back and moved towards Erzurum, where the Seljuks insulted the Mongol ambassadors. The Mongols retaliated by taking Erzurum and massacring its population, and the Mongols then retreated to amass more troops in Georgia and Armenia. Kaykhusraw succeeded in enlisting the help of Achaea, the Empire of Trebizond, the Ayyubids, and even Crusader mercenaries. The 30,000-strong Mongol army moved into Seljuk territory in 1243 and defeated Kaykhusraw's 60,000-strong army in June 1243 at Kose Dag (near Sivas), launching a feigned retreat before ambushing and destroying the Seljuk vanguard. The Seljuks were again forced to become Mongol vassals, but the Mongols would periodically return to enforce their rule.